EISCO 6pc Optical Lens Set, 2" (50mm) Diameter - 3 Double Convex Lens & 3 Double Concave Lens - 200mm, 300mm, 500mm Focal Lengths - Optically True Glass - Ground, Beveled Edges

I was excited about receiving the lenses . The lenses are high quality and I would recommend this to anyone . To microscopic to telephoto lens . It'll keep me busy . You can't find the selection when you come to a store . They are useful , since I am going to build a telephoto lens for my camera . And they are inexpensive also . I saw the same lenses at other sites twice the price . I am really satisfied with this purchase .

I bought these lenses for a science lesson on optics. They were perfect. I was able to use two of them to make a simple telescope using a cardboard tube. The students were completely fascinated by their shape.

Great lenses for straightforward, simple optics experiments. Sturdy enough to not worry that folks will break them. Polished edges keep fingers safe.

Nice glass lenses, just not what I was wanting. I was looking for bow scope lenses and these showed up in my search. I ordered by mistake. Received them the next day. Nice clear lenses but focal length too short. I returned them immediately.

The lenses arrived in record time and are exactly what i need for my basic telescope project. Highly recommend these lenses. Thank you!

One of my students had been having trouble with eyesight for months. She looked through the correct lenses and was amazed that the board was now visible and could be read!

Very good price/value. Clear glass, and if you don't have an understanding of what a certain focal length implies, then don't buy these random lenses. However, there seems to be somewhat of a grainy surface on some of the lenses rather than a smooth surface. Some small chips as well. I only noticed this under CLOSE INSPECTION (I'm picky) under a fairly strong light though, and I'm sure it won't affect performance in any noticeable way (I intend to make an optical bench). The convex lenses produce a nice clear image of my sunlight backyard on a wall. Placing the 20 cm and 50 cm FL convex lenses 70 cm apart will produce a mag. of 2.5x, for those interested in making a demo Keplerian telescope. By using a diverging lens as a "barlow"/focal extender while also adding another converging lens to the eyepiece system can produce higher magnifications still. Great product; would recommend. Just those surface imperfections on some lenses I'm not happy about.

Nice quality, no chromatic aberration. The size enables a good wide field of view when a lens is held close to the eye. The 20mm lens is my preference for checking small print or objects. A student could build a low-power telescope with a pair of these lenses.